About

Space Launch System, the putative replacement for the Space Shuttle for future large missions.

The Space Launch System (SLS) is meant to use Shuttle legacy hardware to build a larger launch vehicle for missions beyond earth orbit.

The core is powered by four RS-25D or E engines. (RS-25D are leftover SSME's from the Shuttle program. The RS-25E is meant to be a cheaper to build non-reusable version of the SSME). The center core booster is based around the diameter and design of the Space Shuttle External Tank, stretched and strengthened to carry a load directly above, instead of hanging off the side.

The SRBs are 5 segment versions of the Shuttle 4 segment SRBs.

None of it is recoverable, differing from the Shuttle program.

Initial payload, without a better upper stage will be in the 70 metric tonne range. With a future high ISP upper stage, the expectation is reaching 130 metric tonnes, allowing single launches to Mars of large enough payloads to be useful for humans.

Launch rate is expected to be very low, as infrequently as once every 2-4 years which will be a difficulty to overcome by the system.